1. Field of the Invention
The present invention relates to an image sensor, and particularly relates to an image sensor with an anti-blooming mechanism.
2. Description of the Prior Art
A pixel of an image sensor has a photodiode to generate charges according to light and a transfer switch coupled to the photodiode to control the charges selectively output to a floating diffusion. In order to well control the charge leakage, for example the transfer switch being an n-type transistor, a negative control voltage is provided to a control terminal of the transfer switch. Under exposure, the photo diode converts light into charges. If the light is too bright, however, a large quantity of charges are generated and accumulated in the photodiode, and leakage current may likely occur to affect the neighboring pixels. Such situation is called blooming.
Therefore, a good mechanism for avoiding the bloom issue is needed.